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71.
72.
本文建立了准确预测多环芳烃(PAHs)及其烷基衍生物的正-辛醇/水分配系数(Kow)模型。模型表明PAHs的分配性质可用零阶价分子连接性指数(~°x~v)描述,~°x~v数值与PAHs的logKow成正比。应用本模型可以预测大范围PAHs的logKow值。 相似文献
73.
气相分子吸收光谱法测定水中的氨氮 总被引:1,自引:0,他引:1
应用气相分子吸收光谱法测定水中的氨氮,测定了该方法的检出限、精密度和准确度,并对实际样品进行了测定和加标回收实验,发现该方法的精密度及准确度均较好,在实际应用当中有一定的优越性,同时也存在一些问题有待改善。 相似文献
74.
用气相分子吸收光谱仪测定水中的硫化物,对其工作曲线、精密度等进行了试验,表明方法简便、快捷、精密度、准确度都较好,适用于各种水质硫化物的测定。 相似文献
75.
76.
设计新型的DNA探针,其主要功能区域包含适配体区域和分子信标互补区域;当无靶标存在时,羧基荧光素(FAM)的荧光被黑洞猝灭基团(BHQ)猝灭,加入靶标后,Ag+与适配体区域特异性结合,使得分子信标与其互补区域发生结合,加入EXO Ⅲ后,分子信标被酶解,从而释放Ag+/DNA探针复合物用于下一轮反应,同时产生大量的FAM,因此,可以通过荧光的增强来定量检测靶标的含量.评价了该方法的灵敏度和选择性,探究它在实际样品中的表现能力.结果表明,适配体区域与分子信标间隔2个碱基的DNA探针与分子信标结合效果最好,检测的信噪比最大.该方法对Ag+的检测最低下限(LOD)为0.1nmol/L,在0.5~200nmol/L范围内,荧光值与靶标浓度成线性关系(R2=0.994).对实际样品的检测在20~200nmol/L范围内呈线性关系(R2=0.998),且能很好的从混合样品中区分10nmol/L Ag+.该研究建立的快速检测Ag+方法具有良好的线性定量能力和操作性能,且灵敏度高、特异性强,可满足现实的需求. 相似文献
77.
低浓度甲醛(Formaldehyde,FA)可以促进细胞增殖.本实验选用K562细胞为实验对象,用不同浓度的甲醛溶液处理细胞,探究其中可能存在的分子机制.测定细胞活力及胞内氧化损伤程度后,发现当甲醛浓度为75μmol·L~(-1)时,细胞增殖率上升(p0.05或p0.01),Warburg效应中的丙酮酸激酶M2型同工酶(PKM2)、葡萄糖转运蛋白1(GLUT1)、乳酸脱氢酶A(LDHA)、葡萄糖和乳酸含量上升(p0.05);此外,细胞周期调控因子Cyclin D-cdk4与转录因子E2F1含量也上升(p0.05).同时,细胞内氧化损伤加强,其中活性氧簇(reactive oxygen species,ROS)含量上升(p0.01),还原型谷胱甘肽(glutathione,GSH)下降(p0.05).然而,在加入抗氧化剂VE后,氧化损伤程度减弱,细胞增殖率降低,PKM2、GLUT1、LDHA、葡萄糖、乳酸,Cyclin D-cdk4、E2F1含量均下降.结果表明低浓度甲醛可能通过氧化应激诱导Warburg效应和影响细胞周期调控因子两条途径促进细胞的增殖. 相似文献
78.
79.
Combined fluorescence and electrochemical investigation on the binding
interaction between organic acid and human serum albumin 总被引:1,自引:1,他引:0
Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules. 相似文献
80.
Synthesis, characterization, and adsorption performance of Pb(Ⅱ)-imprinted polymer in nano-TiO2 matrix 总被引:1,自引:0,他引:1
Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(II)-imprinted polymer for selective
separation and enrichment of trace Pb(II) from aqueous solution. The prepared material was characterized by using the infrared
spectra, X-ray di ractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal
adsorption condition of adsorption trace Pb(II) from aqueous solutions on Pb(II)-imprinted polymer. The equilibrium was achieved
in approximately 4.0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption
capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed
that selectively adsorbed rate of Pb(II) on Pb(II)-imprinted polymer was higher than all other studied ions. Desorption conditions of
the adsorbed Pb(II) from the Pb(II)-imprinted polymer were also studied in batch experiments. The prepared Pb(II)-imprinted polymer
was shown to be promising for the separation and enrichment of trace Pb(II) from water samples. The adsorption and desorption
mechanisms were proposed. 相似文献